Phase 3 Trial of Factor XIa Inhibitor Asundexian Halted for Lack of Efficacy

Bayer announced earlier this week it has stopped the OCEANIC-AF phase 3 clinical trial investigating the factor FXIa inhibitor asundexian for the agent’s lack of efficacy compared to apixaban, a factor Xa inhibitor, in patients with atrial fibrillation (AF) at risk for stroke or systemic embolism.¹ The decision to halt the trial was based on guidance from the study’s Independent Data Monitoring Committee (IDMC), according to the company.¹

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The IDMC, however, did recommend continuation of the OCEANIC-STROKE phase 3 study, another in the Bayer multinational 3-study OCEANIC clinical trial program evaluating asundexian in patients with AF at risk of stroke and in patients who have had an acute noncardioembolic ischemic stroke or high-risk transient ischemic attack (TIA).¹

“Although the results from this analysis do not support the continuation of the OCEANIC-AF study, we will continue investigating asundexian in the OCEANIC-STROKE study and are currently reevaluating other indications in patients in need of antithrombotic treatment,” Christian Rommel, PhD, member of the Executive Committee of Bayer AG’s Pharmaceutical Division and Global Head of Research and Development, said in the company statement.¹

Asundexian is a once-daily, oral investigational agent that targets the FXIa protein involved in pathological thrombus formation but does not affect hemostasis. The drug’s selective action on the coagulation cascade is responsible for its preventive properties against stroke without a corresponding increase in risk for bleeding. Asundexian is not approved for use in any country.¹

OCEANIC program

OCEANIC-STROKE, initiated in January 2023, is a randomized, placebo-controlled, double-blind, parallel group and event-driven phase 3 study investigating the efficacy and safety of asundexian for prevention of ischemic stroke compared to placebo on top of standard-of-care antiplatelet therapy in patients after an acute non-cardioembolic ischemic stroke or high-risk TIA/mini-stroke. Estimated enrollment in the study is 9300 and Bayer has set a primary completion date of October 2025.¹

Bayer announced the third study in the OCEANIC program, OCEANIC-AFINA, on November 10.² OCEANIC-AFINA is randomized, placebo-controlled, double-blind, parallel-group, 2-arm phase 3 study comparing the use of asundexian with placebo in adults aged 65 years and older with AF at high risk for ischemic stroke who are considered ineligible for oral anticoagulant therapy due to an elevated risk of bleeding.²

“The promising clinical results we have seen so far indicate that asundexian could mark a new option for antithrombotic treatment for a broader range of patients,” said Rommel in an announcement for OCEANIC-AFINA.² “It is our vision to support patients with atrial fibrillation, including those, that up to now were deemed as not eligible for treatment with OACs...With OCEANIC-AFINA we will evaluate asundexian in a vulnerable untreated patient population.”²

The study is not yet recruiting participants and, according to Bayer, the company will now reevaluate its design in light of the decision to end OCEANIC-AF.¹

In other news related to progress in investigations of factor XI/Xia inhibitors, findings from the phase 2 AZALEA-TIMI 71 trial were reported by Anthos Therapeutics at the American Heart Association 2023 Scientific Sessions held November 10-13, 2023.³ AZELEA-TIMI 71 compared the factor XI inhibitor abelacimab with factor X inhibitor rivaroxaban for major and clinically relevant nonmajor bleeding events in individuals at moderate-to-high risk of stroke.³ The trial was stopped early (September 2023) due to what Anthos described as “an overwhelming reduction” in these bleeding events.⁴ The preliminary findings showed abelacimab 150 mg reduced major bleeding by 74% compared to rivaroxaban and abelacimab 90 mg reduced major bleeding by 81%.³

Participants randomized to rivaroxaban were allowed to switch to abelacimab in an extension study.⁴

References
1. OCEANIC-AF study stopped early due to lack of efficacy. News release. Bayer. November 19, 2023. Accessed November 21, 2023. https://www.bayer.com/media/en-us/oceanic-af-study-stopped-early-due-to-lack-of-efficacy/
2. New asundexian Phase III study to include patients with atrial fibrillation ineligible for oral anticoagulant treatment. News release. Biospace. November 10, 2023. Accessed November 21, 2023. https://www.biospace.com/article/releases/new-asundexian-phase-iii-study-to-include-patients-with-atrial-fibrillation-ineligible-for-oral-anticoagulant-treatment/
3. New anti-clotting medication reduces bleeding among people with atrial fibrillation. American Heart Association. November 12, 2023. Accessed November 12, 2023. https://newsroom.heart.org/news/new-anti-clotting-medication-reduces-bleeding-among-people-with-atrial-fibrillation?preview=8afe
4. Atrial fibrillation study with abelacimab stopped early by the data monitoring committee due to an overwhelming reduction in bleeding as compared to a DOAC (direct oral anticoagulant). News Release. Anthos Therapeutics. September 18, 2023. Accessed November 21, 2023. http://anthostherapeutics.com/wp-content/uploads/2023/09/2023-09-18-Anthos-Press-Release-final.pdf